Fracture behavior of a four-point fixed glass curtain wall under fire conditions

• Full-scale experiments were conducted to investigate fracture behavior of four-point fixed glass curtain.
• Significant parameters of glass braking under fire were recorded for analysis and comparison.
• Fixed form was identified as a key factor of different breaking behaviors.
• The supported points locate at 10 cm and 5 cm from edges, respectively, which are recommended in practical engineering.

The cracking and subsequent fallout of glazing could significantly affect compartment fire dynamics by creating a new opening for air to enter. Twenty-four 1200×1200×6 mm3 soda-lime glass panes in eight different fixing forms were heated by a 500×500 mm2 N-heptane pool fire to investigate the influence of fixing conditions on glass breakage and fallout. The time of crack initiation, behavior of crack propagation, heat release rates, central gas temperatures, glass surface temperatures and loss of integrity of the glazing assembly were investigated. The relationship between fixing form and crack behavior is discussed, based on the experimental results. The results show that all the cracks initiated at the supporting point and intersected rapidly, causing glass fallout. Mechanical stress caused by supporting pins and thermal stress caused by glass temperature difference (ranging from 48 °C to 159 °C) are the causes of breaking for this kind of curtain wall. It is concluded that various fixing locations have a significant effect on glass breaking. Among the eight cases, the glass panes whose supporting points were located at 10 cm (Case 1) or 5 cm (Case 8) from the edges performed best: these support locations are recommended in practical engineering because of the good fire resistance and structural beauty of such panes.